Electric heater assemblies



Aug. 24, 1965 L. D. DRUGMAND 3,202,796

ELECTRIC HEATER ASSEMBLIES Filed March 26, 1963 INVENTOR. LESTER D DRUGMAND MW WM ATTORNE/S United States Patent 3,232,796 ELECTRIC HEATER ASSEMBLIES Lester. D. Drugrnand, Pittsburgh, Pa., assignor to Edwin L. Wiegand Company, Pittsburgh, Pa. Filed Mar. 26, 1963, Ser. No. 268,125

' 2 Claims. (Cl. 219-318) They present invention relates to heater assemblies, more particularly to electric immersion heater assemblies of the type adapted to be projected through a container wall for heating the liquid contents of the container, and the principal object of the invention is to provide new and improved structures-of such character.

For supplying domestic. hot water, it is common practice to provide a water storage tank in which a sheathed,

electric resistance heating element is immersed. The eleture between the element and the tank must be leak-proof under all pressures to which it will normally be exposed.

Heretofore, it has been common practice to provide a fitting on the tank wall surrounding its aperture and to provide the element with a radially outwardly extending flange which may be sealably clamped to the tank fitting. Unfortunately, since the element flange seals against the fitting, the latter must have a leak-proof juncture with the tank wall, such juncture usually being provided by welding the fitting to the tank. As will be evident, the provision of a leak-proof weld between the tank and the fitting is a relatively high-cost operation which adds considerably to the priced the water heater.

In my application Serial No. 34,723, entiled', Electric Immersion Heater Assembly, filed June 8, 1960, and assigned to the same assignee as the present case, (now Patent No. 3,111,572) it was proposed to eliminate the necessity of providing a sealed juncture between the tank and the fitting by'so forming the element mounting flange that it sealed directly against the tank wall about the aperture through which the element projected. This was an important advance in reducing water heater costs;

however, the necessity of providing a forged mounting flange on the element added somewhat to the cost of the latter. The present invention permits use of a simple,

flat mounting flange on the element without requiring the tank fitting to be attached by leak-proof connection. These and other advantages will readily become apparent from a study of the following description and from the drawing appended hereto.

In the drawing accompanying this specification and forming a part of this application there is shown, for purpose of illustration, embodiments which the invention may assume, and in this drawing:

FIGURE 1 is an exploded, perspective view of the invention,

FIGURE 2 is an assembled sectional view generally corresponding to the line 2-2 of FIGURE 1,

FIGURE 3 is a perspective view of a detail, and

FIGURE 4 is a sectional view of a modified detail.

With reference to FIGURES 1 and 2, 10 represents a portion of the wall of a water heater tank having an aperture 11 therethrough. Suitably secured to the exterior of the tank 10 as by welding :or the like 12, is a support plate 13 having an opening 14 aligned with tank aperture 11 but larger than the latter to leave exposed an 3,262,796 Patented Aug. 24, 1965 "ice annular, tank wall surface 15, margining the tank aperture. It will be noted that the welds 12 are discontinuous and merely serve to secure the support plate 13 to: the tank, it being wholly unnecessary that a liquid-tight juncture be provided between the tank and the plate. For a purpose to appear, threaded openings 16 are formed in the support plate 13 radially outwardly of the plate opening 14.

Turning now to the heater assembly associated with the tank, such assembly is herein shown to comprise the usual hairpin shaped, tubular electric resistance heating element 17 having terminal portions in side-by-side relation. Projecting axially of the element terminal portions are the usual terminal conductor pins 18 to which electrical power connections will ultimately be made.

Secured to the terminal portions of element 17 in any suitable, fluidtight manner is a fiat mounting plate 19 through which the element terminal portions project. Such mounting plate may be of generally the same peripheral size and shape as support plate 13 and has apertures 29 for alignment with respective threaded apertures 16 of support plate 13.

Encircling the element 17 and interposed between the element mounting plate 19 and the tank surface 15 is a ring-like spacer 21 preferably formed of metal or other rigid-material. As best illustrated in FIGURE 2, the internal size of spacer 21 is large enough to slip over the element 17 while its external size is small enough to freely fit within the support plate opening 14 but is larger than the tank'aperture 11 so as to abut the tank surface 15. For a purpose to appear, the thickness of spacer 21 is somewhat less than the thickness of support plate 13.

In order to provide a leak-proof juncture between vthe tank wall and the spacer and between the latter and the element mounting flange, the ends of the spacer are preferably faced with a compressible material. In the present embodiment, the spaced ends are faced with rubber which is bonded to respective spacer ends. Moreover, the rubber at the end of the spacer 21 which faces the tank preferably extends across the spacer bore, see FIG URE 3, leaving only a slot 22 through which the element 17 may be inserted. Slot 22 is of a size to frictionally grip the element thereby retaining the spacer and the element against unintentional disassembly dur ing installation of the element with the tank.

To assemble the heating element assembly with the tank 10, spacer 21 will be slid over the element 17 so that one of its rubber covered sides abuts the element mounting flange 19. The element will then be inserted into the tank through the tank aperture 11 until the opposite rubber covered side of the spacer 21 abuts the tank surface 15. Bolts 23 may then be passed through the mounting plate apertures 20 and threaded into respective support plate openings 16 to draw the mounting plate toward the tank wall. With the bolts 23 drawn the proper amount, the opposite rubber covered sides of the spacer 21 are compressed against the tank wall 10 and the mounting flange 19 to provide a liquid-tight closure for the tank wall opening 11. At the same time, the mounting flange 19 is preferably drawn to abutment with the support plate 13 to positively limit the amount the bolts 23 may be threaded and thus prevent any distortion of the tank wall 10 or the mounting flange 19.

In the embodiment seen in FIGURE 4 wherein like parts are identified with the same reference characters as before but with the sutfix a added, the bore of spacer 21a is preferably also coated with rubber to protect the ring-like core of the spacer against corrosion from exposure to the water contained in the tank. Thus, the ring-like core may be made of low grade steel or the like without consideration to its corrosion resistance. Moreover, the rubber at the spacer end which faces the 7 herein described may be variously changed and modified, without departing from the spirit of the invention; and that the invention is capable of uses and has advantages not herein specifically described; hence it will be appreciated that the herein disclosed embodiments are illustrative only, and that my invention is not limited thereto. a

I claim: p '1. The combination of a hot tankand an electric immersion heater for heating the contents of said tank, said tank having an opening in a defining wall and a supporting flange rigidly secured to said wall and disposed exteriorly thereof, said supporting flange having an opening therethrough which is aligned with but is larger than the tank opening so as to leave exposed a lip provided by the tank Wall surface margining said tank Wall opening, and said heater including a sheathed electric heating element extending through-said tank opening and into said tank and amounting flange secured to said sheath and extending crosswise thereof, said mounting flange having a flat portion overlying said supporting flange and said lip and spaced laterally from the latter, a rigid annular member around said sheath and having opposed end surfaces respectively adjoining said lip and said mounting flange flat portion, said annular member having annular gaskets of resilient material bonded respectively to each end surface thereof, a said gasket at at least one end of said annular member extending across the bore thereof and being apertured to frictionally receive therethrough said heating element sheath, and means drawing said mounting flange toward said supporting flange to seal the gasket at one end of said annular member against said lip and to seal the gasket at the opposite end of said annular member against said mounting flange portion to thereby seal the opening in said tank wall against leakage of Water.

2. The construction of claim 1 wherein a layer of resilient material covers the entire internal surface of the bore of said annular member and said gaskets comprise portions of said layer overlying the respective said end surfaces of said annular member.

References Cited by the Examiner UNITED STATES PATENTS 11/63 Drugmand 2l9-3l8 RICHARD M. WOOD, Primary Examiner.

ANTHONY BARTIS, Examiner. 

1. THE COMBINATION OF A HOT TANK AND AN ELECTRIC IMMERSION HEATER FOR HEATING THE CONTENTS OF SAID TANK, SAID TANK HAVING AN OPENING IN A DEFINING WALL AND A SUPPOTING FLANGE RIGIDLY SECURED TO SAID WALL AND DISPOSED EXTERIORLY THEREOF, SAID SUPPORTING FLANGE HAVING AN OPENING THERETHROUGH WHICH IS ALIGNED WITH BUT IS LARGER THAN THE TANK OPENING SO AS TO LEAVE EXPOSED A LIP PROVIDED BY THE TANK WALL SURFACE MARGINING SAID TANK WALL OPENING, AND SAID HEATER INCLUDING A SHEATED ELECTRIC HEATING ELEMENT EXTENDING THROUGH SAID TANK OPENING AND INTO SAID TANK AND A MOUNTING FLANGE SECURED TO SAID SHEATH AND EXTENDING CROSSWISE THEREOF, SAID MOUNTING FLANGE HVING A FLAT PORTION OVERLYING SAID SUPPORTING FLANGE AND SAID LIP AND SPACED LATERALLY FROM THE LATTER, A RIGID ANNULAR MEMBER AROUND SAID SHEATH AND HAVING OPPOSED END SURFACES RECPECTIVELY ADJOINING SAID LIP AND SAID MOUNTING FLANGE FLAT PORTION, SAID ANNULAR MEMBER HAVING ANNULAR GASKETS OF RESILIENT MATERIAL BONDED RESPECTIVELY TO EACH END SURFACE THEREOF, A SAID GASKET AT AT LEAST ONE END OF SAID ANNULAR MEMBER EXTENDING ACROSS THE BORE THEREOF AND BEING APERTURED TO FRICTIONALLY RECEIVE THERETHROUGH SAID HEATING ELEMENT SHEATH, AND MEANS DRAWING SAID MOUNTING FLANGE TOWARD SAID SUPPORTING FLANGE TO SEAL THE GASKET AT ONE END OF SAID ANNULAR MEMBER AGAINST SAID LIP AND TO SEAL THE GASKET AT THE OPPOSITE END OF SAID ANNULAR MEMBER AGAINST SAID MOUNTING FLANGE PORTION TO THEREBY SEAL THE OPENING IN SAID TANK WALL AGAINST LEAKAGE OF WATER. 